Hvymax

Silverado Dually wheels are 16x6.5 just like the stockers. Anyone know a good place for adapters? I'll need a 3.5" spacer adapter combo for the front and just an adapter for the back.

Oldblue

For an HHR, I don’t recommend adapters or spacers, puts to much stress on the bearing hubs, but your building a specific style looking vehicle, I recommend you get hub centric adapter for your application.

Hvymax

Thanks. It shouldn't really add any stress to the front because everything will end up in the stock location. The back will end up wider by about 4" per side.

Oldblue

Then ensure you get hub centric adapters, 65.1 mm . Bolt pattern 5 X 110 mm .
For future readers.

PulpFriction

4”?! . The track or the tire width?

Hvymax

Track. The dually rims are the same size as the stock 16x6.5. only the offset is different. I'll use a spacer/adapter for the front to match the stock track. In the back I'll use an adapter alone and dish out the rim.increasing the rear track about 8" total. I'm on the lookout for some decently priced rims and I'll go from there. Hub Centric looks like a good place to start. I'll see how the rear end holds up. Fabbing something stronger won't be a problem if the stock setup can't handle it.

Lonwane

It's not the rearend that fails but the hubs that hold the wheel.
They were not designed for that extended weight.
Stock HHR's have the centerline of the wheel almost centered on the hub.
Maybe if you fabricate a different carrier or a stronger hub.

firemangeorge

Rim size won't matter if the tire doesn't fit in the wheelwell. Max size tire on a stock body is 26.3 inches. Anything taller like regular truck tires and you'll have to hack up the back quarter panels. Don't think you've got much room to make those wells bigger without some serious body changes. My guess is you'll be butchering up the unibody structural integrity. In other words, unsafe.
For a little visual reference of a 265/70/16 tire leaned against a HHR, look here, post #44..https://www.chevyhhr.net/forums/tire...r-20651/page5/

Hvymax

The rim sizes are exactly the same. The only difference is offset and bolt pattern. I plan on keeping the front at the stock width using spacers dish in as customary with duallies. In the back I will be dish out widening the wheelbase. I'm not planning on any SCCA campaigns. If anything seems overstressed I can modify or go to a different rim. I have air tools, welders and things that cut and bend metal. 40 years of metal fabrication, dozens of welding certifications 6 procedures with my name on them and my CWI stamp on multiple power plants.looking at the stock rear end the crossbar looks bent slightly in the middle like someone tried jacking it up. I'm lifting the front with Malibu struts. I have springs for the back. Absolute worst case I can make new trailing arms using the stock front points that will be welded to an 8,000lb drop axle with the drop facing forward to maximize clearance and moving the axle centerline back a few more inches.a 1/2" thick adapter plate for the bearing assembly. I could even make the width whatever I feel like. A little wider for true dually or narrowed to pull one things in. Trailing arms welded directly to the axle will negate the need for sway bars and be multiples stronger. Getting the axle further from the fuel abomination will better protect everything and the longer arms and travel smooth the ride even further.

firemangeorge

You better plan on running the same size tire on both front and back. Antilock brakes, ESC and TCS will all go bonkers if you run mismatched size tires F/R.